Sheet handling mechanism for sheet feeders



April 30, 1940. GOEBEL ETAL 2,199,170

SHEET HANDLING MECHANISM FOR SHEET FEEDERS Original Filed June 10,1935 10 Sheets-Sheet 1 Zmvcntors W, MMQM;

Cittornegs G. GOEBEL ET AL ,1'30

SHEET HANDLING MECHANISM FOR SHEET FEEDERS 1O Sheets-Sheet 2 April 30-, 1940.

Original Filed June 10, '1935 @wummm "Hum.

Bnnentors George 60c; belh 5%6/7140/7 Gttornegs 10 Sheets-Sheet; 3

am y bmmv \Nw Dww I WNW mg H 8% NNw wNw WNW Q Imnentons George 6oz/oe[/ Sherman Cha/LL'Lcu Ld (Ittornegs G. GOEBEL ET AL Original Filed June 10, 1935 \DL mv April 30, 1940.

sasm' HANDLING MECHANISM FOR SHEET FEEDERS April 30, 1940. a. GOEBEL El AL SHEET HANDLING MEC HANI SM FOR SHEET FEEDERS Original Filed June 10, 1955 10 Sheets-Sheet 5 MM ad a Aprll 30, 1940. GQEBEL AL 2.199.170

.SHEET HANDLING MECHANISM FOR SHEET FEEDERS Original Filed June 10, 19:55 10 Sheets-Sheet 6 I" 7 n. n

a i l l 'o'L IWI April 30, 1940. G EBEL -r' AL r 2,199,170

I SHEET HANDLING MECHANISM FOR SHEET FEEDERS Original Filed June 10, 1935 10 Sheets-Sheet 7 IZW'WJF April 30, 1940. G. GOEBEL r AL SHEET HANDLING MECHANISM FOR SHEETFEEDERS Original Filed June 10, 1955 10 Sheets-Sheet 8 lllllllllllll I 7 3 April 30, 1940. G. GOEBEL ET AL SHEET HANDLING MECHANISM FOR SHEET FEEDERS Original Filed June 10, 1935 10 Sheets-Sheet 9 ZSnventor attorney April 30, 1940-- GOEBEL ET AL 2,199,170

SHEET HANDLING MECHANISM FOR SHEET FEEDERS Original Filed June 10, 1955 10 Sheets-Sheet l0 3nnentors George GOQEQ Alc fhz mafl Gttorncgs arrangement, should the corners of the next low- Patented Apr. 30, 1940 George Goebel and Sherman A.

Chantland,

Baltimore, Md., assignors to Crown Cork 05 Seal Company, Inc., Baltimore, Md., a corporation of New York Original application June 10, 1935, Serial No.

Divided and this application January 20, 1939, Serial No. 252,052

19 Claims. .(Cl. 211-27) The present invention relates to sheet moving mechanisms for sheet feeders, this application being a division of our application for Sheet feeders, Serial No. 25,908, filed June 10, 1935.

The principal object of the invention is to pro-'- vide a sheet feeder of maximum efliciency in delivering but one sheet at a time to the press or other apparatus to which the sheets are to be fed, and which will successfully handle a wide range of types of materials.

Another object of the invention is to provide a sheet separating or rear suction cup mechanism which is arranged to readily separate the upper sheet of material from the next lowest sheet so that but one sheet of material at a time will be moved through the feeder.

In the handling of a stack of sheets, in order to separate the uppermost sheet from the next lowest sheet, it is desirable to bend the rear portion of the uppermost sheet upwardly and suction cups are ordinarily used for this purpose. By the action of the separators used in most types of sheet feeders, the rear portion of the sheet is bent upwardly along a line extending crosswise of the sheet. In handling some materials, particularly thin sheets of metal, when the rear suctioncups tend to bend the sheet on a line extending transversely thereof, the sheet frequently has a tendency to buckle along a line at right angles to its rear edge, resisting the efforts of the suction cups to bend its rear portion.

The rear cup or separator mechanism of the present invention is designed to bend the rear corners of the top sheet upwardly on a diagonal bending line, instead of bending the entire rear portion on a transverse line. Obviously, the corners can bebent much more readily than the entire rear portion, since the buckling tendency of the sheet referred to above will not be encountered. Aside from their function of-bending or upturning the corners of the sheet, the separators of the present invention are also .de-

signed to exert a bending action within the area of the upturned portion. That is to say, each 1 rear corner of the sheet is double bent on diagonal lines, i. e., bent upward from the sheet and also bent around a projecting member. By this est sheet tend to adhere to theupper sheet, they will be forced or snapped away from the upper sheet by reason of their own resiliency.

Another object of the invention is to provide a front suction cup or forwardingmechanism which will be positive in action toward moving the sheet from the pile when its rear corners are released from the suction of the rear suction cups or separators, and which front cup or forwarding mechanism is extremely simple in construction and operation.

The forwarding mechanism of a sheet feeder must lift the uppermost sheet from the stack and then carry it forward to position it upon the feed table, the forwarder necessarily moving upwardly and then horizontally or forwardly to accomplish this movement. Heretofore, it has been necessary to provide complicated cam and trip devices to obtain these movements of the forwarder.

The front cup or forwarding mechanism of the present invention is of extreme simplicity but nevertheless insures that as the uppermost sheets of the stack are successively presented thereto, they will be lifted and-moved forward in the proper manner.

Another object of' the invention is to provide a mechanism which will move adjacent the underside of each sheet as the sheet is passed over the stack gauge plate, tending to remove from the under surface of the sheet any lower sheet which may tend'to adhere thereto, and return the adhering sheet to proper position on the stack.

It has heretofore been proposed to provide spring fingers upon the upper edge of the stack gauge plate, whichxfingers are intended to engage the lower surface of a sheet to, remove adhering sheets therefrom. However, these devices are' .not of the desired efliciency, particularly because, being stationa y, they merely tend to rub or scrape against the lower surface of the sheet and therefore -do not exert sufiicient force to remove a closely adhering lower sheet.

The stripper mechanism of the present invention comprises one or more members positioned adjacent the upper edge of the stack gauge plate and which are so arranged that their upperorsheet engaging edges move in a substantially elliptical path, their movement during a portion of this path being opposed to the forward movement of the sheets. More particularly, the strippers move downwardly and forwardly as the top sheet leaves the stack, then move upwardly and rearwardly adjacent the under surface of the top sheet, and, finally, back against the front edge of the stack so that if the-position of the sheets immediately beneath the top sheet has been disturbed by removal of the latter sheet, they will be restored tov properly aligned position upon the stack.

Another object. of the invention is to provide a. t

fluid flow circuit which is so arranged that oil cannot come in contact with the sheets.

The oil used to lubricate the suction pumps and blowers which respectively supply the suction and the air blasts necessary to lift and separate the sheets frequently works through the flow lines to the suction or blast nozzles which contact with or direct air upon the sheets, -resulting in the sheets becoming soiled.

By the structure of the present invention, the pressure tank in which the pressure pump compresses the air used in the blast directed against the edges of the sheets is positioned above both this pump and the suction pump of the apparatus, and the remainder of the flow circuit is arranged so that any oil in the circuit will remain in or drain to the tank and thence to the suction pump, which has its outlet connected to the inlet of the pressure pump, thereby obviating all possibility of oil reaching the elements of the circuit which are in proximity to or contact with the sheets.

Another object of the invention is to provide a novel form of drive for the various mechanisms of a sheet feeder.

Other objects and advantages of the invention will be apparent from the following specification and drawings wherein:

Figure 1 is a plan view of the feeder.

Figure 2 shows the left hand side of the feeder in elevation.

Figure 3 is a longitudinal vertical section through a portion of the machine taken on the line '3-3 of Figure 1.

Figure 4 is a detail view showing the valve casing of the feeder in verticaltransverse section.

Figure 5 is a horizontal sectional view taken on the line 5-5 of Figure 4.

Figure 6 is a longitudinal vertical sectional view of a portion of the machine taken on the line 6-6 of Figure 1.

Figure 7 is a view taken on the line i? of Figure 14 and showing the front suction cup or feeder operating mechanism.

Figure 8 is a transverse sectional view taken on the line 88 of Figure 14.

Figure 9 is a view partly in plan and partly in horizontal section showing the mechanism for operating the rear suction cups or separator mechanism.

Figure 10 shows one of the rear suction cups or separators partially in longitudinal vertical section, and also shows in dotted lines the various positions of the separators.

Figure H is a diagrammatic showing of the operating cam for the rear suction cups.

Figure i2 is a vertical sectional view of the rear suction cup operating mechanism taken on the line l2-l2 of Figure 9 or the line l2--l2 of Figure 1.

Figure 13 is a detail view showing oneof the rear suction cups or separators in extreme raised position.

Figure 14 is a longitudinal vertical sectional view of a portion of the apparatus taken on the line H-M of Figure 1 showing one of the front cups or feeders and its operating mechanism in side elevation.

Figure 15. is a transverse vertical sectional view of the apparatus showing the stripper mechanism.

Figure 16 is a vertical sectional view of the Figure 17 is a view similar to Figure 16, but showing the stripper mechanism in another position.

Figure 18 diagrammatically shows, in side elevation, the movement of the stripper bar illustrated in Figures 15 to 1'7.

Figure 19 is a view showing the stack lift control mechanism, with parts broken away.

Figure 20 is a perspective view of the stack lift control mechanism as viewed from left of Figure 19, and

Figure 21 diagrammatically shows the pumps. the motor for driving the same, and the flow circuit and wiring of the machine.

In the following description of the apparatus of the invention, the front of the sheet feeder shown herein is regarded as the end which would be positioned adjacent the press or other apparatus to which sheets are delivered by the feeder. the rear would be the end at which the stack of sheets is positioned for separation by the feed er, and the left and right sides of the apparatus would be these sides as viewed by a person standing at the rear of the feeder and facing the same.

In order that the relation of the mechanisms of the present invention may be more readily understood, the principal elements of a sheet feeder and their related operations are broadly described below:

A stack platform (Figures 1 and 2) is provided at the rear of the machine and on this is carried the pile of sheets, designated by the numeral 5|, the platform 50 being supported on cross bars 52 having their ends removably en-' gaged in the inner runs of pairs of endless chains 53 passing about sprocket wheels on-chain driving shafts 54 as described in our said original application. The chain driving shafts 54 are driven from a shaft 55 extending transversely of the feeder and rotated step by step during the normal operation of the machine from a main cam shaft 56 by means of a pawl and ratchet mechanism 51. The main cam shaft 56, upon which are mounted or from which are driven all of the timing elements or cams of the machine, is preferably driven from a main drive shaft 58 (Figure 9) extending from the press or other apparatus to which the sheets are delivered by the present feeder.

The lifting of the platform' 50 causes the uppermost sheet of the stack 5! to be presented to rear suction cups or sheet separators 59 and front suction cups or forwarders 8i]. The rear suction cups 59 are positioned above the rear corners of the uppermost sheet on the stack (Figure 8) and will descend to lift and bend these corners, the line of bending being diagonally of the sheet. A blast of air is simultaneously directed beneath each lifted corner to separate or float the upper sheet from the next lowest sheet. Just before the suction of the rear cups is released and while the sheet is floating, the front suction cups or for warders 60 move downwardly (Figure 7) and engage the front portion of the sheet, lifting it and then moving it forwardly over a stack gauge plate 6i against which the front edges of the sheets in the stack contact.

As the sheet moves over the upper edge of the stack gauge plate 6!, a moving stripper 62 (Figures i6 and 17) engages the undersurface of the forward portion of the sheet to remove therefrom any sheet which might otherwise adhere to the uppermost sheet and to return the adhering sheet to the stack 5!.

The sheet stack 6 I is kept at a height to permit .the uppermost sheet to be engaged by the senr not at the proper heightas described in our said original application Serial No. 25,908. Y

The forwarders 88 position the sheet upon driven outfeed rolls 68 included in the feed ,table 66,'hold-down rolls 66 press downwardly upon it to hold it in contact with the rolls 68. so that it will be movedalong the feed table, and during the initial portion of this movement it passes through a calipering or gauging mechanism 61. As described in our divisional application Serial No. 252,051 for Calipering mechanism filed of even date herewith, the calipering'mechanism is so designed that if but one sheet passes through the same, it will be permitted to move forwardly along the feed-table 65 to the press-or'other apparatus to which the feeder delivers. If two sheets simultaneously pass through the calipering mechanism, this mechanism will operate to Should three sheets pass simultaneously through the calipering mechanism, the reject member will be raised and the main clutch 68 of the machine,

provided on the main cam shaft 56, will be 'disengaged to stop the operation of the feec'le'r.-

The suction and compressed'air required in the operation of the machine is provided by pumps 18 and H, respectively, (Figure 20) driven by a motor 12 mounted on the feeder and beneath the feed table 65, the flow of fluid being controlled by a valve mechanism 18. As described in our said original application Serial No. 25,908, the

motor 12 may also be connected through a clutch 18, preferably of the magnetic type, to raise or lower the stack platform 58 when it is necessary to change stack platforms,- that is, to insert a full platform in place of one from which the sheets have been entirely removed by the forwarders 68. During such operation, the lift control pawl and ratchet mechanism 51 is disconnected. 8

The machine frame and stack supporting structure The frame of the feeder of the present invention comprises front standards 88 and -8I, -respectively positioned on the right and left sides of the machine. A side plate 82 is fixed to the standard 88 and a side plate 88 extends upwardly from the left-hand standard 8|. Rear standards or uprights 88 are spaced from the standards 88 and8I and are connected to the side plates 82 and 88, respectively, by horizontal beams 85. The uppermost portions of the side plates 82 and 88 are connected by a transverse beam 86 beneath which is positioned the main cam shaft 56. The upper ends of the rear uprights 88 are similarly connected by a horizontal beam 81. A horizontal beam 88 is fixed to the side beams intermediate their ends.

The chain driving shafts 64. are supported beneath the sidebeams 86 in depending brackets 88, best shown in Figure 2, and a .pair of spaced sprocket gears 88 is fixed to each of these shafts, the lift chains 68 moving about these sprockets. .The lift chains 68 are of endless form and their lower ends hang free. In order to hold the outer runs of the chains in proper engagement with the sprocket gears 88, a fixed rod 8| is supported brackets 88, rod 8| carrying a roller 88 in alignment with each of the chains 68, which rollers force the links of the chains 68 to remain in intermeshed relationship with the teeth of the sprocket gears 88, as shown in Figure 2.

.in downward and outward extensions 82 of the.

The stack supporting platform 68 is preferably in the form of a runner of the type used on. industrial trucks, that is, ithas skids or feet 88 upon its side edges, the runner being positioned in the machine in such a manner by the operator that the skids 88 will be arranged transversely of the machine. The platform 68 is supported, during the operation of the machine, upon the cross bars 52 as best shown in Figure 2. These cross bars are provided with hook members at each end thereof, as described in our said original application, to engage the chains 58.

The rear suction cups or separators- The rear suction cup or separator mechanism 58 isshown in. plan in Figure 1 and is shown in forward end is journalled for vertical upward swinging movement upon the cam shaft 56. A vertical plate H5 extending downwardly from the intermediate beam 88 of the main frame is shaft H8, the effective cam surface of cam I28 being its periphery I2I. Cam I28 is arranged to engagerollers I22 mounted on the lower ends of levers I28 journalled on pins I28 fixed in-the side walls of the casing body H8, with the result that the levers I28 will be swung. The upper ends of the levers I28-extend through the upper wall of the casing body H8 and rods. I26 are'pivotally connected thereto. The opposite ends of the rods I25 are connected to jointed suction cup supporting elements I26, which elements include outer arms I21 and inner arms I28, these two arms being pivotally connected. by a pin I28 and the inner arm I 28 being pivotally supported at I28a upon an extension I 88 rigid withand extending diagonally from the casing body H8.

The rods I 26 are preferably'formed in two sec- As is best shown in Figure 9, the pin or stud I 28 suctionline I86 leading tothe valve mechanism '18 of the machine. The outer arm I21 is provided with-an abutment face I86 on its upper side at its inner end, which abutment is adapted to contact with a shoulder I31 on the inner arm I28 when the outer arm is raised.

The gearing connecting the main cam shaft 56 with the shaft 8 is such that the cam shaft 56 will make one revolution to each half revolution of shaft I I8, that is, the separator actuating cam I will operate the separators through a complete cycle by a 180 rotation. Figure 11 diagrammatically illustrates the contour of 180 of the periphery I2I of cam I20 and shows how the cam roller I22 of one member II2 would be actuated thereby, it being understood that the remainder of the cam is a duplication of that shown in this figure so that the other member II2 would be actuated in synchronism.

In the operation of the rear suction cup or separator mechanism, when the diametrically opposite high portions I areopposite the rollers I22 on levers I23, the suction cups will be in the extreme upper' position indicated in dotted lines at 132a of Figure 10. As the cam I20 rotates in the direction of the'arrow of Figure 11 to position the inclines I 4| of the cam I20 opposite the cam rollers I22, the upper ends of the levers I23 will move rearwardly to permit the suction cups I32 to drop by gravity upon the surface of the uppermost sheet of the stack 5|, closely adjacent the rear corners of this sheet. A t this moment the valve mechanism I3 will causesuction to be exerted in the cups I32, causing the corners of the sheets to adhere thereto. The rotation of the cam will subsequently cause the oppositely inclined surface I42 of cam I20 to come opposite the rollers I22, forcing the upper ends of the levers I23 forwardly and raising the outer arms I2I of the suction cup supporting members I26 to a position corresponding to that indicated in dotted lines at I32b of Figure 10, the outer arm I21 turning on the stud I29 of inner arm I28 during its movement. When the position indicated at I322: has been reached, the abutment surface I 36 on the outer 'arm I27 will contact with the shoulder I31 on inner arm I28 and during the subsequent rearward movement of the upper'ends of levers I23, the arms I21 and I28 will move together, the entire jointed member I26 thereby swinging on the pivot I28a at the inner end of inner arm I28.

The movement of outer arm I2'I with respect to inner arm I28 will cause the upwardly bent corners of the sheets to be bent about the rollers- I3I as indicated in Figure 13. By this action,

.the rear corners of the sheets will be bent on arcuate lines, that is, the corners of the sheet will be bent upwardly from the surface ofthe stack M and will be pressed outwardly intermediate this line of bending andthe extreme outer corner of the sheet by the rollers I3I. Such bending of the corners of the sheet will insure that any lower sheet or sheets which might tend to adhere to and bend upwardly with the uppermost sheet will be snapped away from the latter sheet.

It will be observed that the bending of the uppermost sheet is accomplished along diagonal lines. This method is considerably more effective than the bending of the sheet along a line extending transversely thereof, i. e., parallel with its rear edge, particularly in the handling of sheets of relatively heavy material, such as thin metal. Metal sheets, in particular, frequently resist bending on a'line parallel to their rear edge because such sheets are not always perfectly flat but may be curved from edge to edge.

If a sheet is even imperceptibly curved or bent from edge to edge, it will tend to resist any bending of the sheet across this curvature with such effect that the rear suction cups cannot lift the rear portion of the'sheet. The bending of the sheets on diagonal lines at their corners entirely eliminates the possibility of the bending being resisted by any curvature of the sheet.

By the valve mechanism I3, as hereinafter described under the heading The motor and pump assembly, suction is maintained at the cups I32 until the corners of the sheet are lifted to the extreme raised position, when the suction is released. During the time. that the corners are being lifted, a blast of air will be directed beneath them from blast nozzles I40, one of which is supported rearwardly of each rear corner of the stack as shown in Figure 1 and each of which receives compressed air through the valve mechanism I3. The blasts of air directed beneath the upturned corners of the sheet tend to slightly raise the uppermost sheet from the next lowest sheet so that the uppermost sheet will, in effect, float above the stack upon a cushion of air.

The angle in the pins I29 which support the rollers I 3I positions these rollers in planes parallel to the path of movement of the sheet from the stack when it is subsequently lifted by the forwarder mechanisms t0.

It will be observed that the casing elements H3 and IM entirely enclose the operating shafting of the separator mechanism, obviating all possibility of oil or dirt falling upon the sheets.

It will be noted that by the construction described, the casing II3 may swing vertically upwardly upon the main cam shaft 56 as a pivot. During stack changing operations, an over-travel limit switch IIO (Figures 1 and 21) may be relied upon to stop the upward movement of the stack and should the stack lifting mechanism overrun after the switch has been actuated, the stack will merely swing thecasing I I4 upwardly without damage to the machine.

The front suction cup or forwarder mechanism The positioning of the front suction cups or forwarder mechanisms 60 is indicated in Figures 1, 3 and 12, and one of the mechanisms is shown in detail in Figures '7, 8 and 14.

Two of the forwarders are provided upon the machine, one adjacent each side edge of the stack 5|. Since the construction of the two forwarders is identical, the following description of the detailed construction of one will apply to both.

Each forwarder is supported from the trans-- verse beam 86 as best shown in Figure 14, the supporting frame I of the forwarder being rigid with the beam. The supporting frame or casting I50 is in the form of a bar or beam extending in a direction lengthwise of the machine and having its ends curved downwardly as indicated at Hi. The ends of rods I52 are supported in bores providedin the downwardly that suction will be exerted by the cup I12 when upwardly facing cam track I54, best shown in Figure 14. A plate I55 is' flxed to eachside f the bar or beam I50 adjacent its forward end (right-hand'end in Figures '7 and 14), these plates extending downwardly to a point somewhat below the rear plate I55 and serving to support. between them a pin I56 for a purpose hereinafter set forth. I

A carriage I51 is slidable upon the trackway formed by the rods I52, the carriage I51 having bores extending therethrough to receive the rods. From the forward end of the carriage I51, the

right-handend of Figures 7 and 14, there extends a link I58 which is pivotally connected to the upper portion of the carriage I51 by means and thereby the movement of the carriage I51 to be adjusted, and its forward end (righthand end of Figures 7 and 14) is pivotally connected to a lever I50 mounted to swing on the side of the lever I50 and member I61 beingsimilarly connected to a bracket I58 secured to a bar I50 extending transversely of'the apparatus.

,By the above arrangement, it will be obvious that the carriage I51 will be tended to the position shown in solid lines in Figures 7 and 14 by the spring I65 and that the movement of. the high portion of cam I62- against the roller I-I on lever I60 will draw the carriage forwardly or to the right in Figure 14 against the action of the spring.

A suction cup or sheet engaging element I12 fixed to the lower end of a rod I13 is supported upon links I14 and I15 pivotally connected to the rear end of the carriage I51. Link I15 is pivoted on a pin extending between trunnions I15 on the extreme upper portion of the rear end of the carriage and is pivotally connected to the upper end of the cup carrying rod I13. Two

' links I14 are pivotally connected to the lower rear portion of the carriage, one on either side thereof and both extending inwardly to be pivotal'ly connected to the cup supporting rod I15 intermediate the length of the latter, Links I14 and I15 are of equal length and the distances between the axes of their pivots upon both the car-- riage and the cup supporting rod I15 are the same, with the result that the links will always .be parallel. The lower links I 14 have rollers I11 journalled on their outer sides and these rollers are adapted to move along the members of cam track I54 when the carriage recip'rocates.

As shown in Figure 14, the rear end of each of As is hereinafter deit contacts with the surface of the uppermost sheet of the stack, this suction becoming effective immediately prior to the release of the suction in the rear suction cups of separate mechanism.

The operation of each forwarder mechanism 50 is as follows: As the high portion I520. on the cam I52 on main cam shaft 56 moves from a position opposite the roller I5I on operating lever I50, the spring I55 will force the carriage I51 from the position indicated in dotted lines on Figure 14 to the rear, or left as viewed in Figure 14. The carriage will move along the trackway I54 with the rollers I11 of lower links 7 :1

I14 bearing on the high portion of each cam track I54, thereby holding the suction cup at the height indicated in dotted lines. However, as the carriage reaches the rear end of the trackway, the rollers I11 will move down the inclines I19 of the cam tracks, permitting the suction cup to move almost straight downwardly to a position in engagement with the top sheet as indicated in solid lines in Figure 14 as the low portion I522) of the cam comes opposite roller I5I. The valve mechanism 13 will cause the suction to be effective at this moment, and the continued rotation of the cam I52 to turn the high portion I62a again opposite the roller I6I will cause the operating lever I50 to be moved forwardly toward the dotted line position indicated in Figure 14. The resulting movement of carriage I51 to the right (Figure 14) will cause the rollers I11 to move up the inclines I18 on the cam tracks, causing the suction cup to be sharply lifted to raise the leading edge of the sheet in an almost vertical line. Whenthe rollers I11 reach the high portion I80 of the cam tracks, the suction cups will be raised to the height indicated by the dotted line showing thereof in Figure 14, thereby raising the leading edge of the sheet above the upper edge of the stack gauge plate 6| and the stripper bars 62,

The forward movement of vthe cups I12 at this height will position the leading edge of the sheet slightly above the upper surface of the driven outfeed rolls 54 included 'in the feed table 55. After a short length ofthe sheet has passed over the rolls 64, the suction in the cups I12 will be released and the hold-down rolls 55' will be moved downwardly upon the upper surface of the sheet to hold it in engagement with the driven rolls 54 so that the sheet will beadvanced through the calipering mechanism 51 by the rotation of the latter rolls.

Thearrangement of the above mechanism whereby the cups are moved into engagement with the uppermost sheet by the action of a spring such as I65 enables the cups to be properly positioned upon the stack despite a certa'in variation of the height of the stack such as might result from the fact that one side of the stack is slightly' higher than the other.

The stripper mechanism The stripper mechanism 52 is shown in relacent their upper ends with the offset portions adapted to move into and out of notches I86 in the upper edge of the gauge plate M. The upper ends of the bars I85 extend slightly above the upper edge of the gauge plate, the offset portions, in normal position, thereby serving to gauge the front edges of the uppermost sheets in the stack.

Two stripper bars I85 are preferably provided, one adjacent each side of the gauge plate 6I, but the number may of course be varied.

Intermediate their length, each stripper bar has fixed thereto a forwardly extending strap or trunnion I81 positioned about an eccentric I88 fixed to a shaft I89, which shaft is journalled in bearings I96 secured to the forward side of the gauge plate. The lower end of each stripper bar I85 is curved outwardly from gauge plate 6I as indicated at I9I and is positioned in a bracket I92 fixed to the gauge plate. A set screw I93 is provided in each bracket to limit the movement of the lower end of the bar toward and from the gauge plate, the screw I93 being positioned to permit the bar to slide beneath the same as is hereinafter described and also, in effect, serving as a pivot point for the bar. A bracket I94 is fixed to the gauge plate above the shaft I89 to guide the outward swinging movement of the bar with respect to the gauge plate. The shaft I89 is rotated by a sprocket chain I96 or the like driven by a sprocket I91 on the main cam shaft .56. One run of the chain may pass. about a guide roller 255 on the shaft 252 carrying the driven outfeed rolls 64 as shown in Figure 15.

The operation of the stripper mechanism is as follows: The rotation of the eccentric I83 exertspressure upon the trunnion I81 and the adjacent surface of the stripper bar I85 to cause the upper end of the bar to move through the following orbital path indicated by the arrowed line in Figure 18 and from the normal position shown in Figure 16. The upper edge of the stripper bar I85 first moves downwardly and forwardly as the leading edge of the sheet leaves the stack by the action of the forwarders 60, the set screw I93 and curved lower end I9I of the bar permitting this movement. As the sheet continues to move forward, the upper end of the stripper bar continues its movement in an orbitalpath, now moving upwardly and still further forwardly to a point beneath the periphery of the outfeed rolls 64. At the time that the leading edge of the sheet is well past the center line of the rolls 64. the stripper bar will move upwardly and rearwardly as shown by the arrowed line in Figure 18 adjacent the under surface of the forwarder supported sheet so that its upper end will engage the leading edge of any sheet which might have been dragged forward out of proper position on the stack 5|. The stripper bar will then move rearwardly and downwardly to complete its orbital movement and to return any displaced sheet to its normal position on the stack. As is indicated by the dotted line in Figures 16 and 17, the upper ends of the stripper bars move in an elliptical orbit which is of particular effectiveness in returning displaced sheets to proper position on the stack.

The platform lift control mechanism most sheet thereof can be engaged by the front suction cups I12 of the forwarder mechanisms 60 to enable these cups to properly engage the surface of the uppermost sheet; the power for raising the platform under such conditions, that is, during the operation of the feeder, being furnished from the main cam shaft 56.

The main cam shaft 56 of the machine is driven from a shaft 58 (Figures 1 and 6) extending from the apparatus to which the feeder delivers sheets.

The construction of the lift control mechanism is described in detail in our original application Serial No. 25,908. Its operation is as follows: As the front suction cups I12 are lowered to contact with the uppermost sheet on the stack 5I, a projection I13a at the upper end of each of the cup supporting rods I13 will move toward the flange 2II on the trip member 63. Should the portion of the stack beneath that front suction cup be at such height that it is not necessary to lift the stack before the cups descend again, the downward movement of the suction cup will be so limited by the stack that the shoulder I13a of the cup rod will not come into contact with the flange 2 of trip 63. Immediately subsequent to this downward movement of the suction cup, the lift drive eccentric 235 on the main cam shaft 56 will move-to a position to impart a downward movement to pawl operating rod 233, moving the pawl 229 to the left as viewed in Figure 20. However, since lift control trip 63 has not been moved by the downward movement of the suction cup, the pawl hold-out member 224 will be in inward position shown in Figure and therefore in the path of movement of pawl 229, preventing the pawl from engaging the teeth of the ratchet wheel 226, so that shaft 228 will not be rotated, and the stack platform will remain in its former position.

In the event that the stack is at such height that either front suction cup I12 must move downwardly to a position approximating its extreme limit of downward movement to contact with the uppermost sheet of the stack, it would, of course, be necessary that the stack be raised before the suction cups again descend. This action will be accomplished due to the fact that when either suction cup moves downwardly a greater than predetermined distance, the shoulder I13a thereon will come into contact with the flange 2 of trip 63, moving this trip downwardly against the action of spring 2I2 so that the far end 2 I6 of corresponding lever 2I4 will be raised, thereby rocking the rod 2I8. The above described turning movement of rod 2I8 will be transmitted through its arm 222 and the link 223 to move the flange 225 of pawl hold-out member 224 upwardly, thereby moving the latter member outwardly (to the right in Figure 20) and away from the ratchet wheel 226 to the dotted line position shown in Figure 19. As a result,

when the bell crank 232 and the pawl 229 carried thereby are swung to the left (Figure 20), the shaft 228 will be turned and the pinion 236 thereon will rotate to permit the larger pinion 231 on the lifting drive shaft 55 to turn the latter shaft. Such rotation of shaft 55 will rotate the chain drive shafts 54 to raise the platform 58 before the suction cups I12 again descend.

The distance which the platform 50 is raised by each movement of the lifting pawl 229 is preferably slightly greater than the thickness of a sheet of the material which is being handled by the feeder. With such a setting of the lift con-- five such strokes and the uppermost sheet of the stack will thereby be maintained at a height at which it can be readily engaged by the front suction cups.

As is stated in our original application Serial No. 25,908, in the handling of relatively thick sheets of stock, for example metal sheets, it is.

found that the thickness of the individual sheets may vary over the area of one sheet and when such variances are totaled in a. stack from three to five feet high, one side of the stack may be lower than the other. By the present arrangement of having 'a lift control trip 63 positioned adjacent each of the front suction cups, should the stack adjacent that cup be low because of variances in the thickness of the sheets, the trip 63 actuated by that cup will be continuously responsive to this condition and will keep that portion of the stack sufliciently high to permit the cup to engage-that side of the. uppermost sheet. This may, of course, result in the portion of the stack at the other side being at more than normal height, but this will not aflect the operation of the machine since the suction cup at the high side ,of the stack will merely move down a smaller distance'than normal, the shortness of its stroke being accommodated by the spring I65 which moves the suction cups of theforwarding mechanisms 60 to downward position.

The construction of the calipering mechanism 61 and its operation are described in our divisional application for Calipering mechanism, filed of even date herewith. The feed table 65 is described in our said original application Serial No. 25,908.

The motor and pump assembly The motor'12 and the pressure and suction pumps 10 and 1|, respectively, are best shown in Figures 2 and 21. The motor and pumps are mounted on bases secured to the forward sides of the standards 80 and 8|. As best shown in Figure 21, the drive shaft 315 of the motor 12 is a bevelled'gear 382 on shaft 228. As will be hereinafter described, when the clutch 14 is in enaged position, the motor 12, through shaft 380,

will-drive shaft 228'to lift or lower the stack platform 50.

The inlet 885 of suction pump H is connected by a lead 386 to the valve mechanism 13. The outlet of the suction pump is connected by piping 381 to the inlet pipe 100. of the pressure pump 10,

' remainingair required by the pressure pump beingjdrawn through the mouth of inlet pipe 10a. Th'outlet from the'pressure pump is connected by a linev388 to the pressure tank 389, from which extends a pressure line 390 leading to the valve mechanism 13. The lines 386 and 390 may be provided with pressure regulating valves 386a and 3901;, respectively, as shown.

It will be observedthat the pressure tank 309-" is mounted above the pumps 10 and 1| and that the valve mechanism 13 is arranged above the pressure tank. By this arrangement, any oil which might be forced into the pressure tank with the compressed air from pump 10 will settle in the bottom of the pressure tank 389, instead of moving upwardly through the pressure line 390 to the valve casing. A bleed line 39I extends from the lower portion of pressure tank 389 to a point of connection with the inlet 385 of suction pump 10 andline 39I is. provided with a valve 39Ia which will be maintained in almost closed position. This permits oil to settle in the pressure tank sothat the latter, in effect, forms an oil reservoir from which oil flows into the suction pump and thence to the pressure pump, keeping both pumps lubricated, but with no possibility of oil flowing upwardly to the valve mechanism and the suction cups I32 and I12 or blast nozzles I40.

,The pressure tank 389 may be provided with cooling fins 399a to hold the same at a low temperature and thereby prevent oil in the tank from becoming vaporized. So long as the oil does not vaporize, there is little possibility of it being moved from the tank and through the pressure line.

As best shown in Figures 4 and 5, the casing of the valve mechanism 13 is secured to the underside of the cross beam 86, and a rod 395 secured in arms 396 extending downwardly from each end of the valve casing has a plurality of valve operating rocker arms 391 journailed thereon. Each rocker arm is provided on its uppermost end with an adjustable tappet 398 arranged to contact with the outer end of -one of a plurality of poppet valves 399 positioned in bores 400 extending horizontally through the valve casing, the rear ends of the bores being sealed by suitable packing. A spring 40I is provided in each valve chamber, one end of'the.

spring bearing'upon the face of the valve and the opposite end of the spring bearing upon a closure. plate 402 at the fo'rward end of the valve casing. Both the valve ends and the plate 402 may be provided with studs to center the springs thereon, I a

The lower ends of the rocker arms 391 are provided with rollers 403, each roller being adapted to engage one of a series of five cams, generally indicated by the numeral 404 fixed on cam.

seat while when the high portion of the cam.

' is opposite the rocker arm roller, the corresponding valve 399 will be moved to be unseated. As indicated in Figure 4, the valve chamber 406 of each valve is divided into twoseparate chambers whenthe valve is in seated position, one chamber opening from the valve casing through a port 401and the other chamber opening from the valve casing through an outletport 408.

Reading from left to right in Figures 5 and 2.1, the five valves and chambers are designated by the numerals 0, 4H, 2, 4 I3 and 4, respectively. As is shown in these two' figures, the left-hand valve chamber 0 in the valve casing and the third valve chamber 2 from the left have theirports 401 connected by branches 6 and 1, respectively, with the suction lead 396. The other port 408 ofthe left-hand valve 0 is connected to a pipe 8 which terminates in a three-way coupling through which the pipe is respectively connected through branches I84 with with the branches I35 respectively communicating with the suction cups I32 of the separator mechanisms 59. Each of the pipes M and 9 has a return lead, numbered 420 and MI, respectively, connected thereto. Lead 420 of pipe 8 extends to the port 401 of the second valve chamber from the left (4! I) in the valve casing while the lead 42I from pipe 4I9 extends to the port 401 of the fourth valve chamber from the left (3). The ports 408 of the valve chambers 4H and M3 have fitted thereto short ends of tubing 422 having their outer ends turned downwardly to prevent any dirt from falling into the valve chambers with which. they are connected. The right-hand valve chamber 4I4 has its upper port 408 connected to the pressure line 390 leading from pressure tank 389 while its lower port 401 has a pipe 423 connected thereto which pipe extends across the rear of the machine and has the blast nozzles I40 fixed thereto.

The operation of the suction controlling valves described above is as follows:

When the high portion of the cam 404 which controls the rocker arm of the valve chamber 4I0 is opposite the roller 408 on the rocker arm 39! controlling this valve, the valve will be in opened position and suction will be exerted through the line 4'I8 at the suction cups N2 of the forwarder mechanism. At the same time, the low portion of the cam controlling the valve in valve chamber 4II will be opposite the rocker arm of that valve so that the latter will be in closed position. However, when the positions or these two cams are reversed, the valve in chamber 4I0 will be closed so that line 4I8 will be closed from suction main 386. At this time, the valve in chamber 4|I will be held in open position by its cam so that air may flow inwardly through the tube 422, past the valve in chamber H I, through return lead 420 and thence through pipe M0 to the suction cups I12, thereby permitting the sheet which has heretofore been supported by these cups to drop.

The same method of operation will occur with the valve in chambers .4I2 and M3 which control the suction flow to the rear suction cups I32.

The control of the compressed air flowing through lines 390 and 423 is as follows: When the low portion of the pressure valve cam is opposite the roller 403 controlling the valve in valve chamber M4, the valve will be closed and there will be no fiow of air to the blast nozzles I40. When the high portion of the cam moves opposite the roller 403, the valve will be opened and compressed air will flow inwardly through upper port 408, past the valve 399, and out through lower port 401 to line 423. At the proper moment, the cam will permit the valve to again close, thereby shutting off the blast of air.

It will be observed that the valves of the apparatus are thus located in a position convenient for adjustment and, furthermore, the mechanism is very compactly arranged.

The drive mechanism used in changing stacks The drive mechanism used in changing stacks is shown in Figures 19 to 21. As is illustrated in Figure 2.1, and as has been described above, the motor I2 which ordinarily drives only the suction and pressure pumps and II has upon its shaft a magnetic clutch I4 which magnetic clutch is ordinarily disengaged. The driven element of the clutch I4 is carried by a shaft 311 which acts through bevelled gears 318 and 319 to drive ashaft 380 extending upwardly on the left-hand side of the machine as indicated in Figures 1 and 2, the upper end of shaft 380 carrying a bevelled gear 38I which meshes with the bevelled gear 382 on the horizontally arranged cross shaft 228.

As has been heretofore explained, shaft 228 is ordinarily rotated with a step by step rotation by the engagement of pawl 229 with ratchet wheel 226 fixed to shaft 220. Therefore, in order to enable shaft 228 to be continuously rotated to drive shaft 55 and, therethrough, the chain drive shafts 54, it is necessary to hold pawl 229 out of engagement with the ratchet wheel 225. To accomplish this purpose, a pawl hold-out member 440, best shown in Figure 20, is pivoted upon a stud 442 carried in the side plate 83. The hub of the pawl hold-out member 440 is pivotally connected to a link 443, the lower end of the link being pivotally connected to a lever 444 which is mounted for swinging movement on a stud 445, also fixed in the side plate 83. The opposite end of lever 444 is pivotally connected to a small cross head 446 (Figure 2) mounted on the armature 441 of a solenoid 448 fixed to the cross beam 80. By this arrangement when the solenoid 448 is energized through suitable circuits hereinafter described and which are actuated when the feeder is operated for stack changing, its armature 441' will be drawn upwardly, moving the left-hand end of lever 444 (Figure 20) upwardly and thereby raising the pawl hold-out member 440 to lift pawl 229 and hold it out of engagement with the teeth of ratchet wheel 226.

The cross head 446 carries an adjustably mounted stud 450 at its outer end which stud, when the cross head moves upwardly as described above, is arranged to strike the actuating member 45I of a switch 452 mounted adjacent the solenoid 448. Switch 452 controls the flow of current to the magnetic clutch I4 and, by the above arrangement, after the pawl hold-out member 440 has been raised to lift the pawl 229 out of engagement with ratchet wheel 226, the magnetic clutch I4 Will be energized so that motor I2 may continuously drive shafts 311, 380, 228, 55 and 54 to thereby either raise or lower the stack supporting platform 50, according to the direction in which the motor is rotated under the control of suitable switch elements, such as are illustrated in Figure 2 and acting through suitable circuits, hereinafter described.

Should the pawl 229 drop into engagement with the ratchet wheel 226 on shaft 228 before the ratchet wheel has ceased to rotate, particularly during the downward movement of the stack platform, either the pawl 229 or teeth of the ratchet wheel 226 may be broken or chipped. In order to prevent the pawl from dropping too suddenly, a dashpot 415 is provided beneath the cross head 446, the plunger 416 of the dashpot being connected to the cross head 446 to prevent the latter from moving downwardly too suddenly and thereby permitting the pawl 229 from dropping too quickly after the current to solenoid 448 has been cut off.

As is indicated in Figure 21, the motor 12 will be connected to a suitable source of power to enable it to drive the pumps 10 and II during the ordinary operation of the feeder. During such operation the remaining mechanisms of the feeder are driven through clutch 69 by the shaft 58 operated from the press or other mechanism to which the sheets are delivered and the clutch I4 on shaft 316 is disengaged. For stack changing operations, by operation of the proper switch button on the control in Figure 21, the motor 12 may be run (with clutch 14 engaged), in one directionfor lifting the stack table, or rotated in the reverse direction to enable the stack table to be moved downwardly. I

Should the stack be moved too high during stack changing operation, the over-travel limit switch I I will open the circuit to stop the lifting operation of motor 12.

The electrical circuits and the operation of the apparatus controls The feeder is ordinarily controlled from the left-hand side thereof (Figure 2), since the control of the press or other apparatus to which the feeder delivers sheets can be reached from this point. Also, the clutch operating lever 216a of the feeder is within reach of the operator stand-' ing-0n the left-hand side of the feeder. In order to permit the operator to control the feeder during its ordinary operation, a control panel 48| including a Run switch 482 (Figure 21) and a Stop switch 483 is mounted on the standard 8|. During preparation of the feeder for running, or for stack changing operations, the operator would control the feeder from the right-hand When a stack i has been positioned between the chains 53, in order to move the stack upwardly' to position the uppermost sheet thereof within reach of the separators 59 and forwarders 60, the operator would press Up switch 485. This would result in a flow of current from main line 4901) through leads 492, 492a, 493 and 494, relay 495, lead 496, through overtravel limit switch I 10, lead 491, switch 485 and then through leads 498 and 499 to main line 4900. The armature of relay 495 would thus be moved to close the circuits through the four contactors carried thereby. -Currentwouldthus flow from main line 490a through relay contactor 500 to leads 502 and 503 to motor 12. Current would also flow I to the motor from line 4901) through relay contactor 504, lead 506 to motor 12. A third circuit would be established through contactor 501 as" follows: from main line 4900, through contactor- 501 to lead 508 and to the motor, these three circuits causing the motor to be rotated. The pumps would thereby be driven but since the main clutch 69 is not engaged to drive the main cam shaft 56, the various sheet handling mechanisms would not be operated and the fluid from the pumps would be ineffective.

Current would also flow through the fourth contactor 510 to keep the relay closed, 'as follows, from main 4901) through leads 492, 492a, 493 and 494, relay 495, lead 496, overtravel limit switch 0, leads 491 and 4911;, through contactor 5l0, leads M5 and 5l6, normally closed stop switch 488 lead 5|1 through normally closed stop switch 488 and leads 5l8,' 498a and 499 to 'main line 490c; thereby holding the relay 495 closed. In order to actuate the pawl hold-out member 404, a shunt circuit is provided from contactors 501 and 500 as follows: contactor 501,

lead 5l9 through cut-out 5l9a, pawl hold-out actuatlng solenoid 448, lads 520 and 582 and conset' forth above.

tactor 500. Solenoid 448 will therefore be actuated to lift the cross head 446 to raise pawl hold-out member 440 so that the pawl 229 (Fig-- ure 20)- will be disengaged from ratchet wheel 226 to permit shaft 228 to turn freely. Thelifting of cross head 45l will also close switch 452 I so that current may flow from line 490c through leads 499 and 498a, switch 452, lead 522, relay 523, leads 493, 492a and 492 tend to main line 490b, thus closing relay 523 which controls the current to magnetic clutch 14 from the D. C. lines 491a and 49lb through the contac tors of relay 523. and leads 525 and 526, respectively.

The stack platform 50 will move upwardly immediately magnetic clutch 14 is engaged since the motor is already running and the shaft 380 will now be rotated to drive shaft 228 continuously, pawl hold-out member 440 already having been placed in position to maintain pawl 229 lifted. I

The stack 5| will move upwardly until it contacts with overtravel limit switch H0 to break the circuit through relay 495, thereby opening all of the above described circuits, or its upward movement may be stopped by operation of either of "Stop buttons 483 or 488 to opened position, thereby breaking the circuit through relay 495 to open the closed circuits described above.

In the use of the apparatus, a Run switch would next be actuated to set the machine in j normal operation. The circuits closed by the operation of the Run switches will be subsequently described but in order to make the relative arrangement of the circuits more readily apparent, the Down circuit is next described.

In order to move a platform downwardly to enable it to be removed from between the lifting chains 53, Down switch.481 would be pressed inwardly, against its inner set of contacts 481a, thereby causing current to flow through main line 4900, leads 499, 498 and 530, across bridged contacts 481a through leads 53l and 53m,

-relay 532, and leads 493, 492a and 492 to main line 490b. Relay 532 being energized would cause the four contactors thereof to complete the respective circuits in which they are included. More specifically, contactor 534 would close the following circuit: 490a, lead 535, contactor 534, and leads 50!, 502 and 503 to motor 12. Contactor 536 would close the following circuit:

' main line 4900, lead 531, contactor 536, and lead 506 to motor 12. Contactor 538 would close a circuit from 490b, lead 492, contactor 538, and lead 508 to motor 12, thereby causing the motor to beoperated. The fourth contactor 539 of relay 532 will close a circuit to hold the relay energized, as follows: From main line 4900 through lead 499, 498a, 5l8, closed stop switch 483, lead 5", closed stop switch 488, leads 5l6 and H5, contactor 539, relay 532, leads 494, 493, 492a and 492 to main line 490b. A shunt circuit will. be formed from contactor 538 through lead 5l9 by cut-out 5l9'a and pawl hold-out member actuating solenoid 448 and then through leads 520 and 502 to contactor 534. This circuit will actuate solenoid 448 to raise cross head 446, thereby closing switch 452 and resulting in a circuit through solenoid 523 which controls the direct current circuit to the magnetic clutch 14 as Actuation of the clutch will cause the shaft 380 to be operated in the manner already described, but to cause the platform to be moved downwardly, the flow of current to motor 12 having been reversed.

Since the circuit which is holding the contactors of relay 532 in closed position passes through the stop switches .483 and 488, the above operation may be stopped by actuation of either of these stop switches.

The apparatus may be placed in normal running operation by actuating clutch operating lever 216a to move the main clutch 69 to engaged position, thereby causing the main cam shaft.

56 to be driven, and by closing either Run switch 482 or 486 to operate the motor 12 which drives the pumps 18 and H so that the separator and forwarder mechanisms will be effective.

Movement of Run switch 482 to closed position will result'in the following circuit: From or Down switches are operated. The closing of the contactors 555 of relay 554 will result in a shunt circuit from lead 558 to lead 493, as follows: through lead 558a, (including contactors 555) leads 560 and 556, relay 532 and to lead'493. Relay 532 being thus energized, will move its four contactors ,to set up circuits to drive the motor 12 and also to hold both it and the relay 554 energized. The circuits closed through contactors 534 and 536 to motor 12 will be the same as closed thereby during the Down operation described. above and the same will be true of the contactor 538 except that the shunt circuit to solenoid 448 which is closed during Down operation cannot now be closed since the relay 554 holds cut-out 5I9a open, thereby.

preventing flow of current to pawl hold-out member actuating relay 448. The fourth contactor,.

' 539, of relay 532 will close the following circuit:

Main line 4980, leads 499, 498a and 5l8, closed stop switch 483, lead 5H, closed stop switch 488, leads 516 and 5l5, contactor 539, lead 556, relay 532, and leads 493, 492a and 492 to line 4911b. Relay 554 will be on a shunt from contactors 539 and 538, as follows: contactor 539, lead 568, contactors 555, leads 55011, 55! and. 552, the bridged contacts of Down switch 481, lead 553, relay 554, and leads 493 and 49241 to contactor 53.8.

Obviously, the above circuits just described may be broken and the operation of motor 12 stopped uponactuation of either Stop switch 483 or 488, since both of these switches are in the holding circuit.

If Run switch 486 is actuated, current will flow from line 4980 through leads 499, 498 and 530, Run switch 486, the bridged contacts of Down switch 481, lead 553, relay 554, and leads 493, 49211 and 492 to line 4981), thus energizing relay 554. The closing ofthe contactors 555 of relay 554' will result in a shunt circuit from lead 552 to lead 493, as fol1ows:through leads 55l,

550a, contactors 555, leads 568 and 556 and relay 532 to lead 493. Relay 532 thus being energized,

the motor and holding circuits described in con-' nection with the actuation of Run .switch 482 will be set up and actuation of'either Stop switch 483 or 488 will cause the circuits to be opened and motor 12 stopped.

The operation of the separator mechanism 59,

stripper mechanism 62, forwarder mechanism 58 and the operation of the compressed air pump 18 and valves 13, as well as the drive for the entire apparatus, has been set forth in connection with the construction of each of these mechanisms.

Subject-matter disclosed but not claimedherein is claimed in our original application Serial No. 25,908, filed June 10, 1935, or in our other divisional application for Calipering mechanism, filed of even date herewith.

It will be understood that the invention is not limited to the details of construction shown in the drawings and that the examples of the use of the machine and mechanisms which have been given do not include all of the uses of which they are capable, and that the phraseology employed in thespecification is for the purpose of description and not of limitation. v

We claim:

1. The combination in a sheet feeder arranged to deliver sheets to a second apparatus, of sheet stack supporting means, sheet handling means, fluid pump means to provide a desired pressure of fluid at said handling means, means driven from said second apparatus to move said supporting and handling means, and a second driving means to operate said pump means.

2. The combination in a sheet feeder arranged to deliver sheets to a second apparatus, of sheet stack supporting means,,sheet handling means,

fluid pump means to provide a desired pressure of fluidat said handling means, means driven from said second apparatus to move said supporting and handling means, and a second driving means to operate said pump means, said second driving means being alternatively operative to move said supporting means.

3. The combination in a sheet' feeder including sheet stack supporting means, of 'a pivoted sheet separator arranged to bend a portion of the adjacent sheet of the stack; and means associated and moving with said separator intermediate the latter and its pivot and about which the separator will bend the sheet.

4. The combination in a sheet feeder including sheet stack supporting means, of a pivoted sheet separator arranged to bend upwardly a rear corner of the uppermost sheet of the stack, and

means carried by and moving with said separator intermediate the latter and its pivot and about which the separator will bend the sheet.

5. The combination in a sheet feeder including sheet stack supporting means, of a sheet separator arranged to bend upwardly a rear corner of the uppermost sheet of the stack, said separator being pivotally mounted, and means carried by said separator adjacent its pivot and about which the separator will bend the-sheet.

6. The combination in a sheet-feeder including sheet stack supporting means of a sheet separating mechanism pivotally connected at its inner end to the frame of the feeder, said mechanism comprising arms pivotally connected to form a jointed lever, sheet engaging means car ried by the outer end of said lever, means to move said end of said lever upwardly to bend a portion of the engaged sheet, the adjacent ends of the arms of said lever being arranged to project toward the upturned portion of the sheet during I ner end to the frame of the feeder, said mech- 

